1. Field of the Invention
The present invention relates to signal processing circuits, and more specifically to the design and implementation of a second order trans-impedance filter with a single operational amplifier.
2. Related Art
A general trans-impedance circuit generally refers to a circuit which generates a voltage level (on an output path) proportionate to the magnitude of an input current, as is well known in the relevant arts. A filter, implemented as a trans-impedance circuit, provides frequency selective transmission in addition to the current-voltage conversion.
Thus, a circuit or a component which operates as both a trans-impedance circuit and a filter can be referred to as a trans-impedance filter. By combining both filtering and conversion to voltage level into a single circuit/component, advantages such as reduction in area/space requirement and power consumption con be attained.
Trans-impedance filters can be used to process current signals in several scenarios. Examples of such scenarios include processing the output current of a current steering DAC or the output current of a down conversion mixer.
Filter circuits are generally implemented as second or higher order filters, since the higher order provides a desired high level of filtering. In addition, it is desirable to implement such filter circuits using a single operational amplifier, since the corresponding implementations would have reduced power and area requirements.
In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.